I've used Old Hickory butcher knives on turkey and even home grown chickens, but I prefer a smaller blade. Four inches is a good compromise lenght.
For the deer, specifically to open the belly skin without cutting into the carcas I like the point either lower than the midline of the blade or you can achieve a similar purpose by having a ridge/hump above the point.
Use no guard or a very small guard as a large guard can get in the way of your grip.
Here is a general purpose knife I made for a guy that shows how the hump can work. I fileworked this one which I wouldn't do on a skinning knife.
Speaking of skinning knives. Some folks still like the upswept style for removing the skin. You have to be careful opening up the carcass, but it can be done. The extra belly is useful for sweeping cuts.